MHT CET : Tips , Tricks and Shortcuts for Physics
Only for MHT-CET (Excluded for Board Exam) How to Solve any Physics Problem : # Draw a Rough Diagram # List down the knowns and unknowns # Use the best Equation # Solve it Symbolically # Arrive on an Answer Additional Critical Tips : # For Graphs , use only formulae . Substitute different values to obtain the graph . # In case of questions on force or components ; look for al the important forces/components . # If all particles of a body are contributing to a quantity , e.g. Moment of Inertia , Gravitational Field , Electric Field , Magnetic Field ; then find the quantity for a small elemental area and then integrate it between appropriate limits . Circular Motion Gravitation # Potential And Total Energy are always negative , while Kinetic Energy and Binding Energy are always positive . Rotational Motion Oscillations # If phase difference is pi/2 , then t = T/4 . If phase difference is pi/4 , then t = T/8 and so on . So , for finding the time taken to travel between 2 points , find the phase difference between the points and then use the result . Elasticity Surface Tension Wave Motion # Apparent frequency increases when Stationary Waves Kinetic Theory of Gases and Radiation Wave Theory of Light Interference and Diffraction Electrostatics # For solving capacitances in series and parallel , draw a simpler equivalent diagram of circuit . When simplifying a circuit , plot points on the circuit to guide you . # When n capacitors of Capacitance C are connected in series , the total resistance is C/n . # When n series of Capacitance R are connected in parallel , the total resistance is nC . Current Electricity # For solving resistances in series and parallel , draw a simpler equivalent diagram of circuit . When simplifying a circuit , plot points on the circuit to guide you . # When n resistors of Resistance R are connected in series , the total resistance is nR . # When n series of Resistance R are connected in parallel , the total resistance is R/n . # If a wire of resistance R is stretched n (l2/l1) times , The new resistance is n2R # In Wheatstone's network , if the network is balanced , the middle resistance is ignored because no current flows through it . # Whenever , a part of circuit confuses you , remove it and see it's role in the circuit . # The effective resistance for a balanced Wheatstone's Network is R # Use Kirchoff's laws for complicated circuits . Magnetic Effect of Electric Current # For increasing the range of an Ammeter n times , Use a Shunt S = G/(n-1) # For increasing the range of a Voltmeter n times , Use a Series Resistance R = G(n-1) Magnetism Electromagnetic Induction # If peak current / emf is asked , use the sine/cosine wave equations and then find the amplitude from equation . Electrons and Photons Atoms , Molecules and Nuclei # Potential And Total Energy are always negative , while Kinetic Energy and Binding Energy are always positive . # All the formulae are applicable to the Hydrogen atom only . If another atom of Atomic Number Z is mentioned , then divide n by Z in the formulae . Semiconductors Communication System